1610s, "a reaction to external stimulation of the sense organs," from French sensation (14c.) and directly from Medieval Latin sensationem (nominative sensatio), from Late Latin sensatus "endowed with sense, sensible," from Latin sensus "feeling" (see sense (n.)). Meaning "state of shock, surprise, in a community" first recorded 1779.

The great object of life is sensation -- to feel that we exist, even though in pain. It is this 'craving void' which drives us to gaming -- to battle, to travel -- to intemperate, but keenly felt, pursuits of any description, whose principal attraction is the agitation inseparable from their accomplishment. [Lord Byron, letter, Sept. 6, 1813]

"to perceive by the senses," 1590s, from sense (n.). Meaning "be conscious inwardly of (one's state or condition) is from 1680s. Meaning "perceive (a fact or situation) not by direct perception" is from 1872. Related: Sensed; sensing.

c. 1400, "faculty of perception," also "meaning, import, interpretation" (especially of Holy Scripture), from Old French sens "one of the five senses; meaning; wit, understanding" (12c.) and directly from Latin sensus "perception, feeling, undertaking, meaning," from sentire "perceive, feel, know," probably a figurative use of a literally meaning "to find one's way," or "to go mentally," from PIE root *sent- "to go" (source also of Old High German sinnan "to go, travel, strive after, have in mind, perceive," German Sinn "sense, mind," Old English sið "way, journey," Old Irish set, Welsh hynt "way"). Application to any one of the external or outward senses (touch, sight, hearing, etc.) in English first recorded 1520s.

A certain negro tribe has a special word for "see;" but only one general word for "hear," "touch," "smell," and "taste." It matters little through which sense I realize that in the dark I have blundered into a pig-sty. In French "sentir" means to smell, to touch, and to feel, all together. [Erich M. von Hornbostel, "Die Einheit der Sinne" ("The Unity of the Senses"), 1927]

Meaning "that which is wise" is from c. 1600. Meaning "capacity for perception and appreciation" is from c. 1600 (as in sense of humor, attested by 1783, sense of shame, 1640s).

late 14c., "capability of being perceived by the senses; ability to sense or perceive," from Old French sensibilite, from Late Latin sensibilitatem (nominative sensibilitas), from sensibilis (see sensible). Rarely recorded until the emergence of the meaning "emotional consciousness, capacity for higher feelings or refined emotion" (1751). Related: Sensibilities.

late 14c., "capable of sensation or feeling;" also "capable of being sensed or felt, perceptible to the senses," hence "easily understood; logical, reasonable," from Late Latin sensibilis "having feeling: perceptible by the senses," from sensus, past participle of sentire "perceive, feel" (see sense (n.)). Of persons, "aware, cognizant (of something)" early 15c.; "having good sense, capable of reasoning, discerning, clever," mid-15c. Of clothes, shoes, etc., "practical rather than fashionable" it is attested from 1855.

late 14c., in reference to the body or its parts, "having the function of sensation;" also (early 15c.) "pertaining to the faculty of the soul that receives and analyzes sensory information;" from Old French sensitif "capable of feeling" (13c.) and directly from Medieval Latin sensitivus "capable of sensation," from Latin sensus, past participle of sentire "feel perceive" (see sense (n.)).

Meaning "easily affected" (with reference to mental feelings) first recorded 1816; meaning "having intense physical sensation" is from 1849. Original meaning is preserved in sensitive plant (1630s), which is "mechanically irritable in a higher degree than almost any other plant" [Century Dictionary]. Meaning "involving national security" is recorded from 1953. Related: Sensitively; sensitiveness.

early 15c., "carnal, unspiritual;" mid-15c., "of or pertaining to the senses," from Middle French sensuel (15c.) and directly from Late Latin sensualis "endowed with feeling" (see sensuality). Meaning "connected with gratification of the senses," especially "lewd, unchaste" is attested from late 15c.

mid-14c., "the part of man that is concerned with the senses," from Old French sensualite "the five senses; impression," from Late Latin sensualitatem (nominative sensualitas) "capacity for sensation," from Latin sensualis "endowed with feeling, sensitive," from sensus "feeling" (see sense (n.)). Chiefly "animal instincts and appetites," hence "the lower nature regarded as a source of evil, lusts of the flesh" (1620s).

1640s, "pertaining to the senses" apparently coined by Milton to recover the original meaning of sensual and avoid the lascivious connotation that the older word had acquired, but by 1870 sensuous, too, had begun down the same path and come to mean "alive to the pleasures of the senses." Rare before Coleridge popularized it "To express in one word all that appertains to the perception, considered as passive and merely recipient ...." (1814). From Latin sensus (see sense (n.)) + -ous. Related: Sensuously; sensuousness.

From early 14c. as "judgment rendered by God, or by one in authority; a verdict, decision in court;" from late 14c. as "understanding, wisdom; edifying subject matter." From late 14c. as "subject matter or content of a letter, book, speech, etc.," also in reference to a passage in a written work. Sense of "grammatically complete statement" is attested from mid-15c. "Meaning," then "meaning expressed in words." Related: Sentential.

Meaning "what one feels about something" (1630s) and modern spelling seem to be a re-introduction from French (where it was spelled sentiment by 17c.). A vogue word mid-18c. with wide application, commonly "a thought colored by or proceeding from emotion" (1762), especially as expressed in literature or art. The 17c. sense is preserved in phrases such as my sentiments exactly.

1749, "pertaining to or characterized by sentiment," from sentiment + -al (1). At first without pejorative connotations; meaning "having too much sentiment, apt to be swayed by prejudice" had emerged by 1793 (implied in sentimentalist). Related: Sentimentally.

Think on these things, and let S______ go to Lincoln sessions by himself, and talk classically with country justices. In the meantime we will philosophize and sentimentalize;--the last word is a bright invention of the moment in which it was written, for yours or Dr. Johnson's service .... [Laurence Sterne, letter to William Combe, Esq., dated Aug. 5, 1764, published 1787]

1610s, originally "watchtower;" perhaps a shortened variant of sentinel, which had a variant form centrinel (1590s); or perhaps worn down from sanctuary, on notion of "shelter for a watchman." Meaning "military guard posted around a camp" is first attested 1630s. Sentry-box is from 1728.

"detached, kept apart," c. 1600, from separate (v.) or from Latin separatus. Separate but equal in reference to U.S. segregation policies on railroads is attested from 1888. Separate development, official name of apartheid in South Africa, is from 1955. Related: Separately (1550s); separateness.

Frequently the colored coach is little better than a cattle car. Generally one half the smoking car is reserved for the colored car. Often only a cloth curtain or partition run half way up separates this so-called colored car from the smoke, obscene language, and foul air of the smokers' half of the car. All classes and conditions of colored humanity, from the most cultured and refined to the most degraded and filthy, without regard to sex, good breeding or ability to pay for better accommodation, are crowded into this separate, but equal (?) half car. [Rev. Norman B. Wood, "The White Side of a Black Subject," 1897]

Specific sense of "sundering of a married couple" is attested from c. 1600. Sense in photography is from 1922. Separation of powers first recorded 1788, in "Federalist" (Hamilton), from French séparée de la puissance (Montesquieu, 1748). Separation anxiety first attested 1943.